Variable-tension shock-absorbing and rebound spring for automobiles and other vehicles.



F. N. SPRAGU'E. VARIABLE TENSION SHOCK ABSOBBING AND REBOUND SPRING FORAUTOMOBILES AND OTHER VEHIGLES.

APPLICATION FILED JAN. 29, 1914 1,125,199, Patented Jan. 19, 1915.

2 SHEETSSHBET 1.

. F. N. SPRAGUE. VARIABLE TENSION snocx ABSORBING AND REBOUND SPRING FOBAUTOMOBILES AND OTHER VEHICLES. APPLICATION IILED JAN. 29, 1914.

1,125,199. PatentedJa'I1.19,l915.

' 2 SHEETSSHEET 2.

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' VERIAQBLEIEJPENSIQW S HOGK-kBSOiR-BIJNG; AEND REBOUND SPRING FORAUTOMQBILEQL meanest AND OTHER VEHICLES.

Specification of Letters Patent. PatemztedaJ an 1:9, 1915-,

Application filed January 29, 1914, SeriaLNo. 315,208.

To all'wliom it may concern Be it known that I, FRANK N, SPRAGUE, acitizen of the. United States. of America, residing in S'edgwickjcountyand State .of Colorado, have invented" anew an usefulVariable-Tension: Shock-Absorbing and ebound Spring for. Automobiles:andother Vehicles, of which 'thlev following is afspecie This inventionrelates to improvements in variable tension, cushioning l'eaf' springsfor automobiles and other vehicles.

The object, of the invention is, first, to provide a vehicle, sprinwhich Bfl OLd S the required degree of sti ness or tension for averageroad and load'conditi'ons, and which is-so arranged as to affordadditional stiffness or tension to meet added stress, result, ing fromthe violent compression and rehound of the said spring, due'to rough anduneven roads second, to provide. a vehicle cushioning leaf spring,compr1s1ng main and supplemental parts so related that the sup-'plemental part coiiperatee witli zthe main part only when additionaltension or stilt ness is required, .to cushion violent shocksoccasioned'by excessive co npression and rebound ofsa1d spring; third,to provlde a vehicle cushioning leaf spring comprising main andsupplemental parts, the combined strength or tension of which is greaterthan is required under average conditions, when the main part aflord'ssufiicient tension, the su lemental part coiiperating. only when thespring "is subjected to excessive com-. nression and rebound, thus.reducing the liability of breakage to a minimum.

These objects are accomplished by the" Q form of spring illustrated inthe accompanying drawings, in Whi h, .7

Figure 1, is a side view of, a semi-elliptical vehicle springconstructed in accordance on the line 3-3 of Fig. 2'. Fig. 4, is a frontwith my invention, and showing the arrangement of the same when used onthe side of a vehicle. Fig. 2', is an enlargedside view partly insection, of one end' of the spring, showing the stirrup which issecuredto theend ofthe supplemental spring, and which is adapted to beengaged by the main spring I when under excessive compression. Fig. 3,isga'i' vertical transverse sectional view view, showing the applicationof the spring to thegforwardaxle of an automobile, the

arranged in the usual manner.

spring being in a reverse position to that shown in Fig. 1. Fig. 5, is aside view of one end of a spring arranged as in Fig' and showing amodification in the arrangement of the stirrup. And Fig.- 6, .is a sideview of an elliptical spring embodying my improvements.

Referring to the accompanying drawings-the numeral 1, indicates the mainpart, and 2. the supplemental part, of. my improved vehicle cushioningspring part being made up of a plurality of independent blades orleaves, which are areach ranged one upon another in the usual mange ner,the improvement being adaptable, to either elliptical or semi-ellipticalsprings. In the construction of my improved spring, I employ a greaternumber of spring meme hers vor leaves, than ,lare' necessary underaverage road conditions, but. the full' tension' of the spring is'notutilized undersuch conditions, so that on smooth roadswhere the springsare not subjected to excessive compression and rebound, the weight ofthe vehicle is cushioned by a portion of the spring members or leavesonly, which aiiord sufficient tension or stifi'ness under such conditions, and permit an easy up. and down swinging movement of thevehicle. But

when rough roads are encountered. causingv violent compression and"rebound of the springs, their fullv strength or cushioning power isbrought into action, and the shock, both on the compression andrebound,;is absorbed so gradually as to eliminate the jerk- ,ing andbouncing eflect common in s rings of the usual construction, where thefu l tension of all of the springmembers is at all times exerted.

In the accompanying drawings, the main part 1, of the springs, isshownmade up of four leaves of varying lengths, arranged in' the usualmanner, and upon the lon est leaf' as shown 2 115, and overthe steppedend 5 are placed the usual U-clips 6, the free, ends of which arethreaded, and pass through and are bolted to a seat 7., in the case of asemi-elliptical side spring, as in Fig. 1, which seat rests upon andpartially surrounds the axle 8 of the vehicle, and is rigidly clampedthereon by the usual clamping member 9. which partially surrounds the Vaxle and is bolted to the spring seat 7. The

seat 7 and clamp 9, are also employed to secure the lower half of anelliptical spring to the axle, where such a spring is used as a sidespring, but when the same is used as a front or, rear spring, is securedto the axle in the usual manner.

The plate 4, when clamped upon the springs, forms a substantial bracewhich prevents breaking of the leaves at their centers where the bolt 3passes through them,

and its stepped ends hold the spring against endwise movement. To theends of the supplementalspring 2, are secured depending ill-shapedstirrups 10, by bolts 11, which I. g passthroulgh the ends of thestirrups, and through the bent end of the longest leaf of the saidsupplemental spring. The ends of the supplemental spring are spaced asuitable distance from the mainspring, the outer portions of which passthrough the said stirrups, and the stirrups extend a suitable distancebelow the adjacent .por-

tions of the main spring. The sides of the stirrups adjacent to theirlower ends, are

provided with one or more apertures 12, the opposite apertures being inline.

I Through one pair of the apertures, in each stirrup, is passeda bolt13, and upon these holts,between the sides of the stirrup, are mountedpieces of tubing 14, which fit loosely on the bolts, and act as rollers.

Figs. 1, 2, and 3, illustrate a semielliptical side spring, having thestirrups above described, and by referring more particularly to Fig. 2,it will be seen that the portions of the main spring which pass throughthe stirrups normally be a suitable distance above the rollers 14:, andconsequently out of engagement with them, and on smooth.

roads the main springs, alone s'up ort the weight of the vehicle, butwhen t e main spring is depressed beyond its normal limit, the portionsthereof lyingbetween the sides of the stirrup engage and bear upon therollers springs are brought into cofiperative action,

andthe shock is thus sustained by the combined tension of the main andsupplemental springs.

- D n the rebound, the rollers engage the underside of the main springuntil the supplemental spring reaches its normal plane,and the mainspring then continues its upward movement until it engages the underside of the su plemental spring, which thus exerts a resi ient downwardpressure on the main spring which serves to gradually check its upwardmovement, and thus 14, whereby the supplemental.

on the depression and rebound the combined tension of the main andsupplemen-' tal springs is utilized.

In Figs. 4': and 5, T have illustrated the spring as arranged whenemployed as an end spring. When thus used, the spring is reversed, andits ends are secured to the The action of form of stirrup shown in Figs.1, 2, and 3,

I however, preferably employ a modified form of stirrup 17, for endsprings, such a modification being shown in Fig. 5. In

this arrangement, the usual clips 18, which prevent separating of theleaves, are dispensed with, and the stirrups 17 are secured to theleaves in such a manner as to take the place ofthese clips 18. Thesestirrups rest upon and are riveted to one of the upper leaves adjacentto its ends, as shown,

so as to be held against lateral movement, and'bolts 19 are passedthrough the sides of the stirrup, and tightly against the under leaf,thus holding the leaves together. A

bolt 20 is passed through the free epds of each stirrup, and this boltsupports a tubular roller 21. The ends of the longest leaf of thesupplemental spring, pass through and beyond the stirrups, a suitabledistance,

and normally stand about midway between the rollers 21 and the underside of the main spring, but when the main spring is depressed farenough, the ends of the supplemental spring engage and bear upon therollers 21, and the supplemental spring is thus brought'into cooperativeaction with the main spring in receiving and absorbing the shock, as inthemanner above described. By the arrangement, the stirrups move withthe main portion of the spring, but as the central portion of the springis depressed to' a greater degreethan the pertlons wh1ch carry thestirrups, it follows that the supplemental spring will also be carrieddownfarther than the rollers 21,

and will therefore engage the said rollers.

In Fig. 6 is shown an elliptical spring,

which combines the action of both the spring shown in Fig. 1 and thatshown in v Fig. 4c, and T have also illustrated both arrangements of thestirrup in connection therewith, the stirrup 10 being shown on the lowerhalf of the spring and the stirrup 17 on the upper half thereof.

The spring herein'described, not only atfords variable tension to meetvarying rea more resilient cushioning can be secured for smooth or evenroads, than could be obtained with springs of the usual construction, asonly the main member of the spring supports the vehicle at such times,and*this 'member is made up of a less number of leaves than the usualspring, and consequently is not so stiff,

Practical use has demonstrated that th spring above described not onlypossesses all the advantages of the common form of spring, but has inaddition the variable tension feature by which the shock due tounevenness in the road is more thoroughly cushioned, thus contributinggreatly to personal comfort, no'less than to the prolongation of thelife of the vehicle.

Having described my invention, what I Patent, is; j

1. A leaf spring comprising a main part made up of leaves of varyinglengths, and

. a supplemental part made up of leaves of supplemental part, throughwhich the outer portions of the main part pass, said stirrups extendingbelow the. adjacent under sides of the main parts, and. rollers carriedby said stirrups and spaced from the under sides of the main part, andadapted to be engaged by the main part when the same is subjected toviolent compression, thereby causing cooperative action o'f'the parts,said supplemental part also acting to cushion the rebound of the mainpart.

2. The combination with a leaf spring comprising main and supplementalparts, of a reinforcing plate midway of the length of the supplementalpart,.having stepped ends, a seat on the under side of the main spring,a bolt extending through said parts, clips resting upon the stepped endof said plate and extending through said seat to clamp the parts ofthe'spring together, and stirrups carriedvby the ends of thesupplemental part, having rollers, the end portions of the main'partpassing through said stirrups, and being adapted to engage the saidclaim as new and desire to secure by Letters rollers when the said mainpart is subjected to violent compression, the supplemental partbeing'adapted to cushion the rebound of the main part.

, In testimony whereof I affix my signature in. presence of twowitnesses.

FRANK N. SPRAGUE.

WVitnesses G. SARGENT ELLIOTT, HERBERT L. CHASE.

